JPH04180380A - Motion detection circuit - Google Patents

Abstract

PURPOSE:To prevent resolution in the minute motion of a pattern from deteriorating by providing high-pass filters for horizontal and vertical directions separately, discriminating whether a signal whose motion is detected based on the presence/absence of separated output shows the motion in the horizontal or vertical direction, and switching the motion processing of a motion adaptive scanning line interpolation circuit in taking a moving image to overwrite. CONSTITUTION:The motion of an image can be detected by extracting horizontal edge parts and vertical edge parts of the present frame and the frame before one of an input luminance signal Y by high-pass filter parts 6a, 6b consisting of differentiation circuits 4a, 4b in the horizontal direction and differentiation circuits 5a, 5b in the vertical direction, and taking difference of one frame, respectively, and it is judged as 'motion' when inter-frame differential signals 15a, 15b for horizontal and vertical edges are present, respectively. Extracted inter-frame differential signals 15a, 15b in the horizontal and vertical directions are set as absolute values at absolute value converters 8a, 8b consisting of ROMs, etc., and after a noise with micro level is eliminated at core ring circuits 9a, 9b, horizontal and vertical edge information are synthesized by a synthesizer 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an image motion detection circuit for a video signal processing circuit of a television receiver such as Clear Vision.

[Prior art]

The motion detection circuit shown in FIG. 7 detects the motion of the image and performs signal processing according to the amount of motion, such as Y/C separation and scanning line interpolation.

The input luminance signal Y is passed through a 1-frame memory 1 and an adder 2, and the difference between 1 frames is taken, and a motion signal 18 of the luminance signal Y is obtained by a low-pass filter 3.

On the other hand, the color signal C, whose phase is inverted for each frame, is outputted from the color demodulator 35 and is passed through a two-frame delay circuit 36 and an adder 39 to obtain the difference between two frames to obtain a motion signal 37 of the color signal C.

Here, the motion signals 18°7 of the luminance signal Y and the chrominance signal C are synthesized 38, and the motion signals are integrated in the time direction using the field memory 14 in order to prevent detection failure for signals that change from field to field. A motion signal 20 is output after being subjected to a spatio-temporal filter 13 process.

As described above, due to the circuit configuration using the low-pass filter 3, movement of the high-frequency component of the luminance signal Y outside the low-pass filter band causes blurring of the image, and particularly, the resolution is significantly degraded when a fine pattern moves.

Furthermore, since the system obtains motion information from the difference in the signals themselves, such as the difference between one frame for the luminance signal Y and the difference between two frames for the color difference signals R-Y and B-Y, it is not possible to detect the direction of motion. , Therefore, video processing according to the direction of movement cannot be performed.

That is, in the motion-adaptive scanning line interpolation circuit for the luminance signal Y, which is composed of the line-to-line average interpolation circuit 22, the field delay circuit 25, the synthesis circuit 26, the scanning frequency double speed conversion circuit 27, etc. shown in FIG. Since processing is performed by an average interpolation circuit 22 to generate the average of the upper and lower lines, when the picture moves in the vertical direction, the sharpness in the vertical direction is lost at the picture edge part, and the sharpness of vertical scroll characters etc. is insufficient.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned conventional example, and prevents deterioration of resolution due to small movement of a picture such as a picture in the high frequency region of the luminance signal Y system outside the low-pass filter band. The purpose is to improve the overall image quality by supplementing the sharpness of picture edges with equivertical sharpness.

[Means to solve the problem]

The present invention adds a high-frequency motion detection circuit for the luminance signal Y system using a high-pass filter and a one-frame difference to the conventional motion detection circuit for the luminance signal Y system using a low-pass filter, and also Separate pass-pass filters are provided for horizontal and vertical use, and the presence or absence of separate outputs determines whether the motion detected signal is horizontal motion or vertical motion,
By switching the motion processing of the motion-adaptive scan line interpolation circuit during moving images, it prevents resolution deterioration due to detailed movement of images, and also improves the vertical sharpness of vertically scrolling characters. be.

[Effect]

As shown in FIG. 1, a luminance signal Y low-frequency motion detection circuit consisting of a field memory, an adder 2, and a low-pass filter 3, high-pass filters 4a and 4b in the horizontal scanning direction, and a high-frequency motion detection circuit in the vertical scanning direction. High-pass filter sections 6a, 6b consisting of band-pass filters 5a, 5b, adders 7a, 7b,
Based on the motion detection circuit for high frequency signal Y, which consists of absolute value converters Ha, 8b such as ROM, coring circuits 9a, 9b, and horizontal and vertical edge difference signals 16.17 output from the coring circuits 9a, 9b. It consists of a circuit configuration including a motion direction discrimination circuit 11, and high-pass filter sections 6a and 6b extract horizontal edges and vertical edges of the luminance signal Y of the current frame and one frame before, and take a one-frame difference between the two. Detect movement in images.

That is, if there are inter-frame difference signals of horizontal and vertical edges, it is determined that there is movement.

The detected horizontal and vertical motion signals 15a and 15b are converted into absolute values by absolute value converters 8a and 8b, and after noise is removed by coring circuits 9a and 9b, horizontal and vertical signals are converted by a synthesizer 10.
Synthesize vertical information.

The motion direction discrimination circuit 11 discriminates the motion direction based on the presence or absence of the horizontal edge and vertical edge difference signals 16 and 17 output from the coring circuits 9a and 9b, and only when motion is detected in the vertical direction (no motion in the horizontal direction). The discrimination output signal 21 is sent to the switch circuit 24 of the motion adaptive scanning line interpolation circuit shown in FIG.
In order to increase the sharpness in the vertical direction, the average interpolation circuit 22 between the upper and lower lines writes the line twice from the side to the interpolation circuit 23.
Switch to the side.

〔Example〕

In FIG. 1, 1 is a memory for delaying the input luminance signal Y by one frame, 2 is an adder that outputs a difference signal between the current frame and the previous frame, and 3 is a low-pass filter that connects the frame memory L and the adder 2. A low-frequency motion detection circuit for the luminance signal Y is constituted by this, and a motion signal 18 is output.

On the other hand, 6a and 6b are high-pass filters each consisting of horizontal differentiation circuits 4a and 4b such as a delay device and an adder, and vertical differentiation circuits 5a and 5b such as a line memory and an adder; an adder that outputs a one-frame edge difference signal 15a of the direction differential circuit 4a+4b;
7b is one of the outputs of the vertical differentiation circuits 5a and 5b.
Adder 8a outputting frame edge difference signal 15b
, 8b is the edge difference signal 15 output from the adders 7a and 7b.
Absolute value converter such as ROM that converts a and 15b into absolute values, 9
Coring circuits a and 9b output a noise-free horizontal edge difference signal 16 and a vertical edge difference signal I7, which constitute a high frequency motion detection circuit for the luminance signal Y.

Reference numeral 12 denotes a synthesizing unit that combines the motion signal 18 output from the low-frequency motion detection circuit of the luminance signal Y and the motion signal 19 output from the high-frequency motion detection circuit of the luminance signal Y via the synthesizer 10, which synthesizes the motion signal 20. is output to the synthesis circuit 26 of the motion adaptive scanning line interpolation circuit shown in FIG.

Further, 11 is a motion direction discrimination circuit which inputs a horizontal edge difference signal 16 and a vertical edge difference signal 17 and outputs a discrimination signal 21, and is a switch circuit for switching the interpolation circuit of the motion adaptive scanning line interpolation circuit shown in FIG. 24.

2 of the motion adaptive scanning line interpolation circuit shown in FIG. 2 is a line interpolation circuit that generates interpolation data using the average value of the upper and lower lines;
3 is a double-write interpolation circuit that interpolates the interpolation data with the same information as the above line; 26 is a synthesis circuit that combines the output signal of the field delay circuit 25 and the output signal of the interpolation circuits 22 and 23 according to the amount of motion of the motion signal 20; A circuit 27 is a double speed conversion circuit that outputs a double speed signal 28 corresponding to a horizontal scanning frequency such as non-interlace.

Horizontal differentiation circuits 4a and 4b and vertical differentiation circuit 5
High-pass filter sections 6a and 6b consisting of a and 5b,
The horizontal edge portion and vertical edge portion of the current frame and the previous frame of the input luminance signal Y are extracted, and the image movement is detected by taking a one-frame difference between the two, and interframe difference signals 15a of the horizontal and vertical edges are obtained. , 15b, it is determined that there is movement.

detected horizontal and vertical interframe difference signals 15a;
15b is converted into an absolute value by absolute value converters 8a and 8b such as ROM, and after removing minute level noise by coring circuits 9a and 9b, horizontal and vertical edge information are combined by a synthesizer 10.

Furthermore, the luminance signal Y high-frequency motion signal 19 output from the synthesizer 10
and the luminance signal Y low-frequency motion signal 18 output from the low-pass filter 3 are combined in a combining unit 12, and the output of the combining unit 12 is stored in a field memory 14 for preventing detection failure for signals that change from field to field. A spatio-temporal filter 13 process is performed to integrate in the time direction using , and the motion signal 20 is output to the synthesis circuit 26 of the motion adaptive scanning line interpolation circuit shown in FIG.

Part 3 is the differentiator circuit 4a of the motion detection circuit for luminance signal Y high frequency range.
, 4b is a single circuit in the horizontal direction consisting of a dot delay circuit 30, an inverter circuit 31, and an AND gate circuit 32. FIG. Indicates the timing of

FIG. 5 shows the polarity and timing of the luminance signal line edge for the image, where (a) shows the horizontal edge tI.

T! The output signal of the differentiating circuit 4b (current frame), (b) is the horizontal edge 13.1. and the output signal of the differentiating circuit 4a of the noise n (previous frame), (c) is the one-frame difference signal 15a of the horizontal edges t, tz, h, ta of the output of the adder 7a and the noise n (if the output is zero, there is no movement). None), (d) is the absolute value converter 8a output signal (positive polarity) of the one-frame difference signal 15a output from the adder 7a, and (e) is the horizontal edge t of the coring circuit 9a output from which noise n has been removed. ,.

This is a difference signal 16 between tz, jl and ta.

Through the edge generation circuit operation as described above, a horizontal edge signal (C in FIG. 6) is detected even in the movement of the high-frequency luminance signal near the color subcarrier frequency fsc shown in FIG. 6, and the absolute value converter 8a, the presence or absence of movement can be detected via the coring circuit 9a.

Note that a in Fig. 6 is the current signal, and b is the current signal for one clock (4 fs).
c) Delayed inverted signal, C is the horizontal edge signal of a+b.

On the other hand, the motion discrimination circuit 11 discriminates the direction of motion based on the presence or absence of a horizontal edge difference signal 16 and a vertical edge difference signal 17 from which noise has been removed from the outputs of the coring circuits 9a and 9b.

To determine motion, ■No edge difference signal in both horizontal and vertical directions; ■No horizontal edge difference signal; vertical edge difference signal; ■Horizontal edge difference signal; no vertical edge difference signal; ■Horizontal; There are four types of motion information including edge difference signals in both vertical directions.

Among the above four types of motion information, in the motion adaptive scanning line interpolation circuit shown in Fig. 2, there are two types of motion information: No horizontal edge difference signal, vertical edge difference signal, which causes a lack of sharpness due to a decrease in vertical sharpness. The motion discrimination circuit 11 discriminates only the information indicating that a signal is present, and the switch circuit 24 shown in FIG. By switching to the writing interpolation circuit 23 side, the vertical sharpness of the moving image is compensated for.

[Effects of the Invention] As described above, the present invention includes a motion detection circuit for the luminance signal Y system using a low pass filter and a motion detection circuit for the luminance signal Y system using a high pass filter and a difference between one frame. In addition, the same high-pass filter is provided separately for horizontal and vertical directions, and it is determined whether the motion detected signal is a horizontal motion or a vertical motion based on the presence or absence of the separate output. By switching the motion processing of the motion adaptive scanning vA interpolation circuit during moving pictures to double writing based on the motion direction discrimination circuit output, it is possible to prevent resolution deterioration due to detailed movement of the picture, and also to prevent resolution deterioration due to fine movement of the picture. By compensating for the sharpness of the image, the overall image quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a motion detection circuit showing an embodiment of the present invention, FIG. 2 is a block diagram of a motion adaptive scanning line interpolation circuit showing an embodiment of the present invention, and FIG. 3 is a block diagram of a motion detection circuit showing an embodiment of the present invention. FIG. 4 shows the timing diagram of the horizontal one-machine circuit of the pass-pass filter section, and FIG. FIG. 6 is an edge timing diagram of a luminance signal near the color subcarrier to explain FIG. 1, FIG. 7 is a block diagram of a conventional motion detection circuit, and FIG. 8 is a diagram of a conventional motion adaptive scanning line interpolation circuit. It is a block diagram. 1 is a frame memory, 4a and 4b are horizontal differentiation circuits,
5a, 5b are vertical differentiation circuits, 8a, 8b are absolute value converters, 9a, 9b are noise removal coring circuits, 10
．． 12 is a signal synthesizer, 11 is a motion direction discrimination circuit, 13 is a spatio-temporal filter, 14 is a field memory, 22 is an average interpolation circuit for the upper and lower lines, and 23 is a circuit for the same information as the upper line.
25 is a field delay circuit, and 27 is a double speed conversion circuit compatible with horizontal scanning frequencies such as non-increment. Patent applicant Fujitsu General Co., Ltd. Figure 2 Figure 3 Figure 4 Figure 5

Claims (4)

[Claims] (1) In a video signal processing circuit such as a television receiver, a first high-pass filter section extracts high-frequency components of the luminance signal Y, and a second high-pass filter section outputs 1 of the luminance signal Y.
The same first frame memory for extracting frame differences.
and a high-frequency motion detection circuit consisting of an adder for the output of the second high-pass filter section, an absolute value converter for the output of the adder, and a coring circuit for removing signal noise, and inputs the one-frame difference signal. and a low-pass motion detection circuit of a low-pass filter. (2) Each of the first and second high-pass filter sections is a horizontal scanning direction high-pass filter consisting of a delay device and an adder, and a vertical scanning direction high-pass filter consisting of a line memory and an adder. and an adder that combines the high-pass filter outputs in the horizontal scanning direction of the first and second high-pass filter sections, and a high-pass filter output in the vertical scanning direction of the first and second high-pass filter sections. 2. The motion detection circuit according to claim 1, further comprising an adder for synthesizing filter outputs. (3) Claim (2) further comprising a motion direction discrimination circuit that discriminates the direction of the one-frame difference output signal of each of the high-pass filter in the horizontal scanning direction and the high-pass filter in the vertical scanning direction using a gate circuit or the like. The motion detection circuit described. (4) The motion detection circuit according to claim 2, wherein a switching circuit between average value interpolation and double-write interpolation of a motion adaptive scanning line interpolation circuit is controlled during moving images by the output signal of the motion direction discrimination circuit.